First there was Facebook. Then Google+ came along with its brand pages. Now Twitter has become the latest social network to embrace marketers when it unveiled its new brand pages yesterday, giving advertisers more options in creating customized profile pages.

The new brand pages will allow advertisers to differentiate themselves from regular Twitter users by displaying their logos and taglines more prominently on a banner that stretches across the page. Brands will also be able to embed photos and videos in tweets at the top of their timelines. What is perhaps most useful for brands is the new design will allow users to separate their @ replies and mentions, making it easier for companies to know when users are communicating directly with them or talking about them.

Twitter's brand pages come about a month after Google launched brand pages for Google+, and both designs are similar to Facebook's platform. The trend toward brand pages is a natural development of businesses following consumers on social networks and looking for ways to carve out their own space, according to Brian Blau, research director at Gartner.

"Hosting branded pages is now table stakes for the popular social networks, and they do tend to compete on a feature-by-feature basis…Both Web and social networks have their place; brands need Web sites to provide detailed information about their businesses in a completely controlled environment, but they also recognize they need to have brand presence where their customers go, and the new Twitter brand pages will give these companies yet another opportunity to tell their stories," he says.

So where does this leave marketers? Facebook is still "the premier place" for social media marketing, eMarketer Principal Analyst Debra Aho Williamson notes, but as other social networks roll out more options, marketers must think harder about how to best allocate their energy and dollars to their social media campaigns.

"Before it was simple: Marketers could launch their campaigns on Facebook and spread it through Twitter," Williamson says. "The challenge is now, 'What do I do where? How much time should I spend on each one?' It makes social media much more complicated."

Twitter's global ad revenue is projected to reach $139.5 million in 2011, and it will continue to grow at a fast pace as the platform rolls out its new ad products, according to eMarketer. By 2013, eMarketer estimates worldwide ad revenues at Twitter will reach nearly $400 million.

In terms of ad revenue, Google is still king, however. EMarketer estimates that the company will bring in $12.8 billion in U.S. ad revenue alone this year, followed by Facebook, which is expected to earn $3.8 billion in U.S. ad revenue in 2011.